Professor Helen McShane has been working on a new TB vaccine for 10 years. There are about 9 million new cases and 1.7 million deaths every year from tuberculosis. She developed MVA85A, a vaccine with the aim to boost the cellular immune response induced by BCG. Developing countries are especially in need of a new vaccine since HIV and TB epidemics overlap and show a devastating synergy.
BCG, now over 100 years old, remains the only licensed vaccine against Tuberculosis. It confers good protection against severe disease and meningitis but doesn’t protect against lung disease. MVA85A was the first vaccine of the new generation to enter into efficacy testing. It is currently being tested in The Gambia, Senegal and South Africa.
Ultimately, medical research must translate into improved treatments for patients. At the Nuffield Department of Medicine, our researchers collaborate to develop better health care, improved quality of life, and enhanced preventative measures for all patients. Our findings in the laboratory are translated into changes in clinical practice, from bench to bedside.
Q: How big a problem is TB today?
HM: TB remains one of the major causes of disease and death throughout the world today. Last year there were 9 million new cases throughout the world and 2 million deaths. In addition, the emergence of multi-drug resistant strains and extensively drug resistant strains of MTB have meant that really we are not very good at treating this disease anymore in those situations. We know that a third of the world's population are latently infected with TB, which means that they are at risk of reactivation of that latent infection if they become immunosuppressed for any reason.
Q: How are tuberculosis and HIV linked?
HM: The geographical overlap between the TB and the HIV epidemic has really had a devastating impact, particularly in sub-Saharan Africa. We know that people who are infected with HIV have a 10% annual risk of reactivating their latent infection, compared with people who are HIV negative who have a 10% lifetime risk. In addition we know that people who are HIV infected are significantly more likely to get new infection with TB. Furthermore we know that people who are infected with HIV who develop TB disease, that TB then causes a progression of their HIV disease so these two pathogens really do have a devastating synergy.
Q: How well does the vaccination protect against tuberculosis?
HM: Vaccination is the most effective and efficient way to control any infectious disease outbreak. BCG is the only available licensed vaccine against TB and has been around for over a hundred years now. BCG is routinely given throughout the developing world at birth and we know that when it's given at birth it is good at protecting against severe disease and TB meningitis in particular, in the first 10 years of life. But we know that BCG doesn't protect against lung disease which is where the burden of mortality and morbidity are. We also know that boosting with BCG (giving it repeated times) doesn't make any difference and doesn't make it any better.
Q: How is your research linked into this?
HM: My research program over the last 10 years has been to develop new TB vaccines and to test them in clinical trials. MVA85A, one of the vaccines we've developed here is now the most clinically advanced new TB vaccine in the world. MVA85A went into clinical trials in 2002 and since then we've conducted 19 clinical trials, first in the UK, then in the Gambia, South Africa, and more recently in Senegal, testing the safety primarily of this vaccine in different populations, in different ages, in TB infected patients and in HIV infected patients more recently. Last year MVA85A entered into a Phase IIb efficacy trial in South African babies and that study will run for the next 2 years when we'll actually find out for the first time whether this vaccine actually works to stop people getting TB disease. Next year we'll start a big study in HIV infected adults as they're also a really important target population for a new TB vaccine.
Q: How does your research fit into translational medicine within the department?
HM: One definition of translational medicine is taking things from the laboratory through into the clinic and that's exactly what we do in my program. MVA85A is a vaccine I made in my PhD and its now the most clinically advanced new TB vaccine being tested in several countries throughout the world.